MacArthur, who represents New Jersey in the House of Representatives, engineered the amendment that allowed the Republican-backed Obamacare replacement — the American Health Care Act — to pass.

According to Politico, MacArthur's moves to pass the bill by negotiating with far-right Republicans caused him to fall out with some of his centrist colleagues.

"I'm not looking to be divisive within the group and I'm not looking to change who I am," MacArthur told Politico. "I'm going to continue to govern the way I believe the American people need us to govern. That means we engage with the Freedom Caucus. We engage with everybody."

After the new health bill passed, MacArthur also faced outrage from his mostly-Democratic district. People crowded in for a town hall and criticized MacArthur for pushing a bill that could cause thousands of people to see their insurance rates soar due to preexisting conditions. In what has since become known as the MacArthur Amendment, Obamacare's restrictions on increasing insurance costs based on previous illnesses might no longer apply.

While many moderate Republicans spoke out against the American Health Care Act, MacArthur insisted that only a small percentage of Americans lose coverage under the new bill.

"This unwillingness to engage with members of our own party is unacceptable to me," he said. A full report on the number of people who could lose health care coverage will be released just one day after MacArthur's resignation.

Still, the former insurance broker told Politico that he intends to remain active in the caucus. After stepping down from the leadership role, he hopes to dedicate more time to negotiating with other Republicans.